Subject: MPSL ASSERT: 69, 108 and HardFault when using ESB (CONFIG_ESB_MPSL_TIMESLOT) with BLE dual connection and ZMS on NCS v3.3.0 / nRF54L10

[Pang0]

Hi,

I'm running NCS v3.3.0 on a Nordic nRF54L10 (nRF54L Series, Cortex-M33) with:
- BLE peripheral role, max 2 connections (dual connected simultaneously)
- ESB in CONFIG_ESB_MPSL_TIMESLOT mode
- ZMS library for non-volatile storage
- ESB PTX/PRX role switching every ~4 ms
(check if TX data pending → enter PTX → after TX done/callback → switch back to PRX)

Under combined BLE traffic (2 connections) + ESB communication, the device randomly crashes:

<err> mpsl_init: MPSL ASSERT: 69, 108
<err> os: ***** HARD FAULT *****
<err> os: Fault escalation (see below)
<err> os: ARCH_EXCEPT with reason 3
>>> ZEPHYR FATAL ERROR 3: Kernel oops on CPU 0
Current thread: 0x20007010 (idle)
Halting system

Key configuration:

# BLE
CONFIG_BT=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_MAX_CONN=2
CONFIG_BT_DEVICE_NAME="RD-QED2"
CONFIG_BT_GATT_CLIENT=y
CONFIG_BT_USER_DATA_LEN_UPDATE=y
CONFIG_BT_CTLR_DATA_LENGTH_MAX=251
CONFIG_BT_BUF_ACL_RX_SIZE=251
CONFIG_BT_BUF_ACL_TX_SIZE=251
CONFIG_BT_L2CAP_TX_MTU=247
CONFIG_BT_CTLR_SDC_MAX_CONN_EVENT_LEN_DEFAULT=5000
CONFIG_BT_RADIO_NOTIFICATION_CONN_CB=y

# MPSL / ESB
CONFIG_MPSL=y
CONFIG_ESB_MPSL_TIMESLOT=y
CONFIG_MPSL_TIMESLOT_SESSION_COUNT=1
CONFIG_MPSL_WORK_STACK_SIZE=2048
CONFIG_ESB=y
CONFIG_ESB_CLOCK_INIT=y
CONFIG_ESB_TX_FIFO_SIZE=16
CONFIG_ESB_DYNAMIC_INTERRUPTS=y
CONFIG_ESB_RADIO_IRQ_PRIORITY=0
CONFIG_ESB_EVENT_IRQ_PRIORITY=1
CONFIG_NRFX_GPPI=y
CONFIG_DYNAMIC_INTERRUPTS=y
CONFIG_DYNAMIC_DIRECT_INTERRUPTS=y
CONFIG_MPSL_ASSERT_HANDLER=n

# ZMS
CONFIG_ZMS=y
CONFIG_PM_PARTITION_SIZE_ZMS_STORAGE=0x4000

My questions:
1. What does "MPSL ASSERT: 69, 108" mean in MPSL timeslot context? Is it an invalid timeslot request or incorrect return from the timeslot signal callback (e.g. p_next == NULL / bad extend action)?
2. Are there known issues/recommendations when toggling ESB PTX⇄PRX inside an MPSL timeslot while BLE (2 connections) is active on nRF54L Series?
3. Could BT_CTLR_SDC_MAX_CONN_EVENT_LEN_DEFAULT=5000 (5 ms) conflict with the 4 ms ESB role-check cycle and cause timeslot overruns / rejected requests?
4. What is the correct / safe sequence to stop ESB (PTX→PRX switch) and re-enter the MPSL timeslot to avoid this MPSL assertion?

Any clarification or reference would be greatly appreciated.

Thanks!

[Kazi Afroza Sultana]

Hello,

Can you try to set CONFIG_MPSL_HFCLK_LATENCY=1650 in the prj.conf file and try again to run the sample?

Thanks.

BR
Kazi

[Pang0]

Hi Nordic team,

Regarding the first issue:

It appears the root cause is related to the 32.768kHz clock offset on my board. Before applying the correction, stopping BLE advertising triggers an assert. This also happens during BLE and ESB coexistence — stopping either BLE or ESB at runtime results in the same assertion failure.

Second question regarding NCS migration:

When migrating from NCS 3.0.0 to NCS 3.3.0, I noticed that the compiled partitions.ymllayout has changed compared to the previous version. Using the default configuration, this difference causes issues when upgrading from older firmware versions.

To maintain compatibility, I added a pm_static.ymlbased on the old partition layout, but compilation fails with the following error:

-- Found partition manager static configuration : D:/00_work/03_multi_tx_rx_shift_optimize/f-e-wireless-shifting/pm_static_nrf54l15dk_nrf54l10_cpuapp.yml
Partition 'mcuboot' is not included in the dynamic resolving since it is statically defined.
Partition 'mcuboot_pad' is not included in the dynamic resolving since it is statically defined.
Partition 'mcuboot_primary' is not included in the dynamic resolving since it is statically defined.
Partition 'mcuboot_primary_app' is not included in the dynamic resolving since it is statically defined.
Partition 'mcuboot_secondary' is not included in the dynamic resolving since it is statically defined.
Partition 'zms_storage' is not included in the dynamic resolving since it is statically defined.
Partition manager failed: Incorrect amount of gaps found in static configuration. There must be exactly one gap in the static configuration to support placing the dynamic partitions (such as 'app'). Gaps found (3):0x10800-0x85000 0xfa000-0xfb000 0xff000-0xfd000 The most common solution to this problem is to fill the smallest of these gaps with statically defined partition(s) until there is only one gap left. Alternatively re-order the already defined static partitions so that only one gap remains.
Failed to partition region flash_primary, size of region: 1036288
Partition Configuration:
mcuboot:
  placement:
    align:
      end: 4096
    before:
    - mcuboot_primary
  size: 65536
mcuboot_pad:
  placement:
    before:
    - mcuboot_primary_app
  size: 2048
mcuboot_primary:
  size: 479232
mcuboot_primary_app:
  size: 477184
mcuboot_secondary:
  placement:
    after:
    - mcuboot_primary
    align:
      start: 4096
  size: 479232
zms_storage:
  placement:
    align:
      start: 4096
    before:
    - end
  size: 16384

Why did the default partition layout change after the migration? Is there a recommended way to keep using the original NCS 3.0.0 partition layout in NCS 3.3.0? Which configurations or files need to be updated?

For reference, I will attach the partitions.ymlgenerated by NCS 3.0.0, the one generated by NCS 3.3.0, and my current pm_static.yml.

Looking forward to your reply.

Thanks!

Fullscreen ncs3.3.0.txt Download

EMPTY_0:
  address: 0xf8000
  end_address: 0xf9000
  placement:
    after:
    - mcuboot_secondary
  region: flash_primary
  size: 0x1000
app:
  address: 0x10800
  end_address: 0x84000
  region: flash_primary
  size: 0x73800
bootconf:
  address: 0xffd080
  end_address: 0xffd084
  region: bootconf
  size: 0x4
mcuboot:
  address: 0x0
  end_address: 0x10000
  placement:
    align:
      end: 0x1000
    before:
    - mcuboot_primary
  region: flash_primary
  size: 0x10000
mcuboot_pad:
  address: 0x10000
  end_address: 0x10800
  placement:
    before:
    - mcuboot_primary_app
  region: flash_primary
  size: 0x800
mcuboot_primary:
  address: 0x10000
  end_address: 0x84000
  orig_span: &id001
  - app
  - mcuboot_pad
  region: flash_primary
  sharers: 0x1
  size: 0x74000
  span: *id001
mcuboot_primary_app:
  address: 0x10800
  end_address: 0x84000
  orig_span: &id002
  - app
  region: flash_primary
  size: 0x73800
  span: *id002
mcuboot_secondary:
  address: 0x84000
  end_address: 0xf8000
  placement:
    after:
    - mcuboot_primary
    align:
      start: 0x1000
  region: flash_primary
  share_size:
  - mcuboot_primary
  size: 0x74000
otp:
  address: 0xffd500
  end_address: 0xffd980
  region: otp
  size: 0x480
sram_primary:
  address: 0x20000000
  end_address: 0x20030000
  region: sram_primary
  size: 0x30000
zms_storage:
  address: 0xf9000
  end_address: 0xfd000
  placement:
    align:
      start: 0x1000
    before:
    - end
  region: flash_primary
  size: 0x4000

Fullscreen ncs3.0.0.txt Download

EMPTY_0:
  address: 0xff000
  end_address: 0xff800
  placement:
    after:
    - zms_storage
  region: flash_primary
  size: 0x800
EMPTY_1:
  address: 0xfa000
  end_address: 0xfb000
  placement:
    after:
    - mcuboot_secondary
  region: flash_primary
  size: 0x1000
app:
  address: 0x10800
  end_address: 0x85000
  region: flash_primary
  size: 0x74800
bootconf:
  address: 0xffd080
  end_address: 0xffd084
  region: bootconf
  size: 0x4
mcuboot:
  address: 0x0
  end_address: 0x10000
  placement:
    align:
      end: 0x1000
    before:
    - mcuboot_primary
  region: flash_primary
  size: 0x10000
mcuboot_pad:
  address: 0x10000
  end_address: 0x10800
  placement:
    before:
    - mcuboot_primary_app
  region: flash_primary
  size: 0x800
mcuboot_primary:
  address: 0x10000
  end_address: 0x85000
  orig_span: &id001
  - mcuboot_pad
  - app
  region: flash_primary
  sharers: 0x1
  size: 0x75000
  span: *id001
mcuboot_primary_app:
  address: 0x10800
  end_address: 0x85000
  orig_span: &id002
  - app
  region: flash_primary
  size: 0x74800
  span: *id002
mcuboot_secondary:
  address: 0x85000
  end_address: 0xfa000
  placement:
    after:
    - mcuboot_primary
    align:
      start: 0x1000
  region: flash_primary
  share_size:
  - mcuboot_primary
  size: 0x75000
sram_primary:
  address: 0x20000000
  end_address: 0x20030000
  region: sram_primary
  size: 0x30000
zms_storage:
  address: 0xfb000
  end_address: 0xff000
  placement:
    align:
      start: 0x1000
    before:
    - end
  region: flash_primary
  size: 0x4000

Fullscreen 6175.pm_static.txt Download

mcuboot:
  address: 0x0
  end_address: 0x10000
  placement:
    align:
      end: 0x1000
    before:
    - mcuboot_primary
  region: flash_primary
  size: 0x10000

mcuboot_pad:
  address: 0x10000
  end_address: 0x10800
  placement:
    before:
    - mcuboot_primary_app
  region: flash_primary
  size: 0x800

mcuboot_primary:
  address: 0x10000
  end_address: 0x85000
  orig_span: &id001
  - mcuboot_pad
  - app
  region: flash_primary
  sharers: 0x1
  size: 0x75000
  span: *id001

mcuboot_primary_app:
  address: 0x10800
  end_address: 0x85000
  orig_span: &id002
  - app
  region: flash_primary
  size: 0x74800
  span: *id002

mcuboot_secondary:
  address: 0x85000
  end_address: 0xfa000
  placement:
    after:
    - mcuboot_primary
    align:
      start: 0x1000
  region: flash_primary
  share_size:
  - mcuboot_primary
  size: 0x75000

zms_storage:
  address: 0xfb000
  end_address: 0xff000
  placement:
    align:
      start: 0x1000
    before:
    - end
  region: flash_primary
  size: 0x4000